Chemistry #2

Periodic Table

• A chart that organizes the elements according to their physical and chemical properties.

• Developed by Dmitri Mendeleev in 1867.

Mendeleev’s two main contributions:

1. organizing known elements according to properties and characteristics

2. recognizing the need to leave spaces for elements not yet discovered

Elements

• A pure substance that cannot be broken down or separated into simpler substances.

• Made up of one kind of atom.

• More than 115 elements discovered

Writing Elements

• Each element is represented by a chemical symbol.

• Chemical symbols consist of one or two letters. The first letter is always capitalized. The second letter is not.

Chemical Symbol Examples

• O = Oxygen

• Au = Gold

• Na = Sodium

Worksheet: Identify & write chemical symbols for common elements

Blank Periodic Table

Elements can be;

Metals • Shiny

• Malleable

• Ductile

• Usually solid

• Good conductors of heat and electricity

Non-metals

• Tend to be gases or brittle solids

• Dull

• Non-malleable and non-ductile

• Poor conductors of heat and electricity

Metalloids

• Solids • Shiny or dull • May conduct electricity

• Poor conductors of heat • Non-malleable and non-ductile

• Properties of both metals and non-metals.

Properties of Transition Metals

• Shiny

• Ductile and malleable

• Conduct electricity

• Conduct heat

• **Label transition metals on your blank periodic table.

What’s in each elements box

• Includes the element’s name, symbol, atomic number and atomic mass.

• Complete Activity 2-2A pg. 49

• Remember the following...

• #p+ = atomic #

• #e-= #p+

• #n = atomic mass – atomic number

• The periodic table is organized into periods and chemical families.

• Periods: the horizontal rows

• Families: the vertical columns

• Elements in the same family have similar physical and chemical properties.

Chemical Families

• Alkali Metals: Family 1 • Highly reactive with halogens

• Reactive with oxygen and water

• Low melting points

• Soft

Alkaline Earth Metals: Family 2

• Less reactive the alkali metals

• Burn in air if heated

• Produce bright flames

• React with water

Halogens: Family 17

• Non-metals

• Highly reactive

Nobel Gases: Family 18

• Very stable

• Un-reactive

• All gases

Transition Metals (Continue to fill in blank periodic tables)

• Found at the centre of the periodic table

• Complex arrangement of electrons

• Three are magnetic; Fe, Co and Ni

Families of the Periodic Table

The Periodic Table and the Atomic Theory

• Energy levels = 2

• Valence energy level = 2

• Valence electron = 2

• Beryllium

Bohr-Rutherford Diagrams

• Most elements in the same family have the same # of valence electrons (# of electrons in the outermost energy level).

• The period # = the # of energy levels.

• The valence shell of the noble gases is FULL; therefore stable

• Gaining or losing electrons will allow atoms to achieve a kind of stability. Metals will lose electrons while non-metals will gain them.